Copper-zinc alloy



Patented Oct. 14-, .1941

COPPER-ZINC ALLOY Wolf Johannes Miller and Moritz Niessner,

Vienna, Germany, assignors to Aktiengesellschaft Dynamit Nobel, Pressburg, Slovakia, a company of Czechoslovakia .No Drawing. Original application June 25, 1938,

Serial No. 215,856. Divided and this application March 13, 1941, Serial No. 383,154. In

Austria July 21, 1934 1 Claim.

This invention is a division of our application Ser."No. 215,856, filed June 25, 1938, for Copper zinc alloy.

It is known that gamma-brass, that is to say copper-zinc alloys with a copper content of about 31-40%, 1. e. alloys which are characterized by a low copper content, are more resistant to corrosion than the brass alloys of the alpha and alpha and beta region with for instance 68-72 percent and more of copper, i. e., a higher copper content. The technical employment of gammaalloys poor in copper is however impossible, since 'these alloys are-extremely hard and brittle and are consequently not machinable.

From such alloys, as is described in our prior Patents Nos. 2,006,598 and 2,006,599, it has been disclosed that it is possible, by the addition of a few percent of a metal soluble in gamma-brass or alloyable therewith, such as nickel or, with more advantage cobalt, preferably by a simultaneous addition of nickel and cobalt, to obtain alloys, which possess the good resistance to corrosion of gamma-alloys poor in copper, but are also capable of being worked up, that is to say can be treated with machine tools and can also be rolled ho't. Such alloys with an addition of approximately 312% of cobalt, nickel or the like individually or in mixture, that isto say for instance pure copper-zinc alloys with a minimum content of nickel of approximately 7. 8% or of cobalt of approximately 545% have extremely good technical properties, and when cobalt and nickel are used simultaneously it is possible with a much smaller cobalt content to obtain the same effects as with the use of cobalt alone. Consequently alloys that are deficient in copper, even those most deficient, can be made utilisable for industrial purposes or as constructional material for the production of articles, if the copper-zinc hereinbefore set forth.

at least a small but efiective amount of one of the metals of the following group:

Percent Iron Up to 1.8 Aluminium 4. Up to 1.5 Silver Up to 2.0 Chromium Up to 3.0 Tin Up to 2.0 Lead Up to 0.3 Selenium 1 Up to 0.6 Tellurium Up to 0.6

but in no greater amounts than are soluble in the solid solution and the zinc constituting substantially the remainder.

, It has been ascertained that such alloys are suitable for cold working, including cold rolling, pressing and drawing and at the same time have a high resistance to corrosion.

In carrying out the invention, the manganese content should be smaller in the case of alloys of higher copper content than in the case of alloys of lower copper content. The higher the manganese content the more suitable is the alloy for Thus an'enhanced workability in the cold canbe imparted to the alloys of the invention, by the addition of suitable amounts of one or more of the elements iron, lead, tin, selenium and tellurium within the limits hereinbefore set forth while their corrosion resistance can be enhanced by the addition of one or more of the metals aluminium, chromium and tin within the limits It is easy to ascertain empirically, the amount of each element that will produce the most favourable eflect.

A suitable alloy in accordance with the invention is one containing between 30 and 45% of p r, between 3 and 12% of cobalt and/or nickel, between 4 and 15% of manganese and between 0.5 and 1.5% of iron.

The addition of up to 0.3% of phosphorus to the hereindescribed alloys is advantageous since it very considerably improves the fineness of structure of the alloys.

By means of the additions according to the invention the range of the solid solution can also be increased, to some extent, beyond that of the binary alloy, and alloys with a somewhat higher copper content which however must be substantially less than 45%, which come within the beta-i-gamma range in the binary alloy, can also be converted into a state corresponding to gamma brass and rendered suitable for applications, such as cold rolling or drawing, from which they are otherwise excluded on account of their copper content.

The following is a typical example of an alloy according to the invention:

Percent Cu 36 Ni 6 Co 2 Mn 10 Fe 1.2 Zn Remainder What we claim is:

A corrosion-resistant copper-zinc alloy which is workable in the cold state, comprising copper in an amount of 30 to 45%, at least one metal of the group cobalt and nickel in an amount of 3 to 12%, manganese in an amount or 4 to 15%, iron 0.5 to 1.5%, and in a small but effective amount which is capable of increasing the corrosion-resistance or the alloy, chromium up to 3%, the zinc constituting substantially all the remainder.

WOLF JOHANNES MULLER. MORI'IZ NIESSNER. 

